Hi,
Today I got a dead APC Symmetra PX Static Bypass Switch 160kW and torn it apart. I found a component (the last photo below) one of my friends told me was an IGBT. Its terminals 2/3 are shorted with a copper bus (the other side is terminal 1 connecting to another bus). It has other terminals 4~7. There are 3 such components in the box (presumably each for one phase). If it's an IGBT, how can it have so many terminals? Does anybody know how this static bypass switch, and this IGBT, work? Where can I find its model number and datasheet?
I don't want to remove it from the heatsink for now because I don't have heat transfer silicon to glue it back.
Thanks.

 

I found this (https://www.galco.com/buy/Infineon/FF400R12KE3?scrollTo=docs) very similar. So it's very probably a half-bridge IGBT module (consisting of two IGBTs). If all of the three are working, maybe I can try them in a BLDC driver.

 

Most probably they are half bridge SCRs couples.

Those packages usually have the DC busbar connections on terminals 2 and 3 while 1 is the midpoint, halfway the bridge.

This is consistent with the wiring in your photos.

If they were IGBTs instead there'd be anti-parallel connected and hence they actually short input and output through the built-in freewheeling diodes.

So, they must be SCRs, just check them for short circuit between 1-2 and 1-3.
Power devices always fail short circuit.

 

Most probably they are half bridge SCRs couples.

Those packages usually have the DC busbar connections on terminals 2 and 3 while 1 is the midpoint, halfway the bridge.

This is consistent with the wiring in your photos.

If they were IGBTs instead there'd be anti-parallel connected and hence they actually short input and output through the built-in freewheeling diodes.

So, they must be SCRs, just check them for short circuit between 1-2 and 1-3.
Power devices always fail short circuit.

Thanks. Yes 2 and 3 are shorted and connected to another busbar for each phase which is not shown in the photos. Will check the modules. I checked online and learned IGBTs are charge sensitive and could be damaged inadvertently so I have not tried to check them with DMM before fully understand how to do so correctly without the risk of damaging them. I know good ones are expensive.
I found the video here helpful

They may be SCRS not IGBTs but this wiring perfectly match the one (IGBT) in my previous post- to me they are oppositely parallel so work for AC the same way as duel way SCRS, or triacs.

 

But you maybe correct. I found this also very similar. https://cdn.sos.sk/productdata/6a/1a/3de84f94/skkt-72-12-e.pdf

Actually you are probably correct, from the name of the switch (static switch) it makes more sense to use SCR instead of IGBT.

Anyway as far as I understand, both a half bridge SCR and a half bridge IGBT would work here.

Any way to tell an SCR from an IGBT using only a DMM?

 

Mmm... not a safe way to tell them apart with a multimeter, for instance G-E should be open in and IGBT and conducting in an SCR, but a faulty IGBT could look like an SCR.

However if they were IGBT they should have been series connected, since they are parallel connected instead, they should definitevily be SCRs.

But let's make a step backward, what is wrong with your unit, cannot switch off or cannot switch on?

In any case just check fo A-K (C-E) short cirtuit first, that's the most probable way to fail of both SCR and IGBT.

And finally, remove them and have a look to label, as long as you don't touch the thermal compund coverd surfaces you can reassemble them without spoliling too much thermal conduction even without new paste

 

Mmm... not a safe way to tell them apart with a multimeter, for instance G-E should be open in and IGBT and conducting in an SCR, but a faulty IGBT could look like an SCR.

However if they were IGBT they should have been series connected, since they are parallel connected instead, they should definitevily be SCRs.

But let's make a step backward, what is wrong with your unit, cannot switch off or cannot switch on?

In any case just check fo A-K (C-E) short cirtuit first, that's the most probable way to fail of both SCR and IGBT.

And finally, remove them and have a look to label, as long as you don't touch the thermal compund coverd surfaces you can reassemble them without spoliling too much thermal conduction even without new paste

No idea what’s the fault of this unit. I took it from scrapyard for fun and parts.
Yes, the A-K connection test suits both. I learned from online that an SCR latches on when triggered while an IGBT doesn’t. So after a connection test I can test with a simple circuit. I can also remove it from the huge heat sink to check the mark.
Thanks very much for your help.
Ps. One more point-just curious, why do you think they must be SCRs if paralleled? From the IGBT datasheet in my previous post, the same wiring (1 as one side of the switch and 2+3 as the other) seems also working. Thanks.

 

Found this out-Model name SKKT 2737 12E. They are SCR pairs ie triacs. Seems working, will do more tests.

Couldn't find the exact model online (strange). Something similar -
https://www.semikron.com/dl/service-support/downloads/download/semikron-datasheet-skkh-27-07897842/

Further question, while I know IGBTs are normally used in BLDC drivers, due to their similarities, can SCRs also be used the similar way? Their specs would probably be an overkill for anything I may work on, just a general question and I would not mind turning them into a BLDC driver if the answer is yes.